I kind of think it isn't just fishing but being outdoors in general that is on the decline. I was looking at some of the park statistics here:
Backcountry camping is back down to 1960's levels but the thing that surprised me the most were some of the frontcountry stats. Front country tent camping has dropped off:
2008 - 142,849 camper nights
1979 - 213,565 camper nights
What really surprised me is the huge level of drop off in RV camping inside the park:
2008 - 118,981
1979 - 215,495
Now if anyone would have asked me I would have thought tent camping would be down less than RV camping. Any year you pick and anyway you look at it there just aren't as many people doing outdoor type activities in the smokies despite a rise in the population in general although the drive through in the car crowd is still going strong most just don't leave the car.
The good news is that whenever you are in the backcountry or the frontcountry in some places you will be experiencing the same number of people that were there in the 60s so overcrowding doesn't seem to be that bad. I have spent a lot of Saturday nights this year at formerly popular backcountry sites and was the only one there. I couldn't believe that there was no one at Rich Mtn cs #5 on a nice October Saturday night. Didn't see hardly anyone on the trails either. The more I see that it just amazes me...